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Kate on Cars - Feb 2014 - Oil Change Intervals


Kate on Cars - Feb 2014 - Oil Change Intervals

by Kate Jonasse

You can change your oil or change your engine – it’s your choice. Changing the oil on time is a lot less expensive than replacing the engine. Not changing your engine’s oil before the oil degrades can reduce the life of your car’s engine, potentially leading to expensive avoidable repairs down the road.

How often should I change my oil?

I recommend changing the oil every 3000 miles or 3 months (whichever comes first) if your engine takes standard oil, and 5000 miles or 5 months if it takes synthetic. I use these guidelines on my own vehicles because I want them to last a long time. Going any longer than these intervals can cause engine oil to gunk up and clog internal components and passages. This leads not only to premature engine wear or failure, but potentially to other symptoms like unusual noises. Is your engine noisier in the morning? This could be due to an oil-level or -quality related issue that should not be ignored.

Already been neglecting your vehicle’s engine? Worry not, some of the damage may be able to be partially remedied by an oil flush, which will soften the gunked-up oil and help clear the passages to allow nice lubricating oil to flow through the engine as it should. If the flush is not done correctly, it can actually damage the engine further, so don’t try this at home – find a shop you trust, ask them about their oil flushing procedure and have only professionals do it. It won’t work if significant engine damage is already done. 

Should I use synthetic oil in my engine?

If the manufacturer recommends synthetic, then yes. Otherwise, probably not.

Synthetic oil is made in a lab and has certain additives that grant it a longer life. It is more free-flowing and has some properties that are different from standard oil. Standard oil originates from the ground.

Newer cars with tighter engine tolerances may be designed to run with synthetic oil. Synthetic oil has special additives that make it hold up to heat without breaking down as fast as standard oil. Using standard oil in these engines can damage them and reduce fuel economy too. Don’t use standard oil in an engine that takes synthetic (unless you’re stranded in a desert and it’s all you have – then get the oil flushed as soon as you get back to civilization).

If the manufacturer of your vehicle recommends a standard oil, switching to synthetic could cause some problems, particularly oil burning or inadequate friction protection. Use they type of oil the manufacturer recommends for your engine. 

But my owner’s manual says I can go 7500 miles between oil changes!?

I advise against going that long in between oil changes on most vehicles. Lower scheduled maintenance costs (what the manufacturer says on paper – not necessarily real life maintenance costs) give car-makers better third-party ratings, like with Consumer Reports. That helps them sell more cars, which is their primary goal. These longer oil change intervals do not necessarily help the cars they’ve already sold last longer.

Many manufacturers consider it normal for an engine to burn up to 1 quart of oil in 1000 miles. So whatever your oil change interval, make sure to check the oil level in between oil changes and top off as needed.

Happy Valentine’s Day, and feel free to email me your car care questions.